In what will be the latest example of western backing for the strategic Balkan state’s membership of Nato and the EU, Matthew Palmer, the US deputy assistant secretary of state, arrives in Skopje on Monday.

Palmer’s visit comes barely 48 hours after Macedonian politicians agreed to initiate the constitutional changes needed to rename the former Yugoslav republic North Macedonia. The knife-edge vote late on Friday followed hours of high drama in Macedonia’s 120-seat parliament.

The US state department went out of its way to welcome the parliamentary result, which was opposed by Russia. In a tweet over the weekend, the department’s spokesperson Heather Nauert said: “The US believes that the Prespa Agreement is a historic opportunity to advance stability, security and prosperity throughout the region.”

The accord – reached with Greece after 27 years of bitter wrangling over the republic’s name – is fiercely contested by Moscow, which has long viewed the ex-communist region as a traditional sphere of influence. Athens says it will lift its decade-long veto against the landlocked state joining Nato after the change of name, which Greeks have long believed implied territorial ambitions against their own adjacent province of Macedonia.

Rightwing nationalists in the opposition VMRO party, backed by Russia, had sought hard to prevent any colleagues endorsing Prime Minister Zoran Zaev’s attempt to amend the constitution – the first step in an arduous process for the country to adopt a new name.

With just 72 MPs, Zaev’s two-party coalition fell eight short of being able to pass the motion without opposition support.

“I wish to thank these brave [opposition] MPs,” the visibly relieved social democrat leader declared after he succeeded in mustering the necessary two-thirds majority. “[They] put the interest of the country and citizens before their partisan interests.”

The dissident MPs were immediately ejected from the VMRO party – making it easier, analysts said, for parliament to endorse further votes in the weeks ahead.

The Greek prime minister, Alexis Tsipras, praised the ballot on Saturday as he assumed the post of foreign minister following the abrupt resignation of Nikos Kotzias last week. In a tweet congratulating Zaev, he described the vote as “a big step towards our common success. A very important step to a prosperous future for our people!”

Under the deal, Greece’s 300-member parliament must follow MPs in Skopje by ratifying the agreement.

Tsipras, whose leftist Syriza party views resolution of the row as a major foreign policy success, vowed to remain in post for “as long as it takes” to see the Macedonia deal through.

But, echoing the drama that has gripped Skopje, Panos Kammenos, who heads the small nationalist Independent Greeks, the coalition’s junior partner, pledged to withdraw its support for the government when politicians were called to endorse the accord. “Our cooperation with Syriza in government, our presence in government … will be until such time when the agreement comes to parliament,” he said Sunday. “Then honestly and cleanly, as we have said, we will withdraw. Our position couldn’t be clearer.”

Kammenos claimed that opposition MPs in Skopje had only agreed to support the name change after receiving €2m (£1.76) in bribes.